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A disproportionately rapid growth of the upper surface of dorsiventral organs, such as leaves, through the stimulus of exposure to light. Encyc. Brit.

(Zoöl.) A light-emitting organ; specif., one of the luminous spots on certain marine (mostly deep-sea) fishes.

mperature, varying according to climate. This is the only way in which a plant is able to organize carbohydrates. All plants without a chlorophyll apparatus, as the fungi, must be parasitic or saprophytic. --Pho`to*syn*thet"ic (#), a. -- Pho`to*syn*thet"ic*al*ly (#), adv.

The influence of light on the movements of low organisms, as various infusorians, the zoöspores of certain algæ, etc.; also, the tendency to follow definite directions of motion or assume definite positions under such influence. If the migration is toward the source of light, it is termed positive phototaxis; if away f…

The tendency of growing plant organs to move or curve under the influence of light. In ordinary use the term is practically synonymous with heliotropism.

n, or of the supposed connection between the various faculties of the mind and particular organs in the brain.

The power of exciting the organs of the brain by magnetic or mesmeric influence.

One of a series of artificial organic dyes made as condensation products of the phenols with phthalic acid, and well represented by phenol phthaleïn. Their alkaline solutions are fluorescent. Phenol phthalein, a white or yellowish white crystalline substance made from phthalic acid and phenol. Its solution in alkalies…

A retrograde metamorphosis of the floral organs to the condition of leaves.

A foliar part of a plant; any organ homologous with a leaf, or produced by metamorphosis of a leaf.

Homologous with a leaf; as, the sepals, petals, stamens, and pistils are phyllous organs.

f the phylon or tribe, in distinction from ontogeny, or the development of the individual organism, and from biogenesis, or life development generally.

Relating to phylogenesis, or the race history of a type of organism. -- Phy*lo*ge*net"ic*al*ly, adv.

A group of simple marine organisms, usually classed as the lowest of the sponges. They have inflated hollow bodies.

Perceptible through a bodily or material organization; cognizable by the senses; external; as, the physical, opposed to chemical, characters of a mineral.

Of or pertaining to physiology; relating to the science of the functions of living organism; as, physiological botany or chemistry.

science of physiology; a student of the properties and functions of animal and vegetable organs and tissues.

The science which treats of the phenomena of living organisms; the study of the processes incidental to, and characteristic of, life.

An organic element of a flowering plant; a phyton.

An organ stop, with a high, piercing tone.